- fd: s32
- flags: u32
- IORING_SETUP_* the ring was created with
- features: u32
- IORING_FEAT_* the kernel reports
- sq_entries: u32
- sq_mask: u32
- sq_head: *u32
- advanced by the kernel
- sq_tail: *u32
- advanced by submit
- sq_flags: *u32
- IORING_SQ_*
- sq_dropped: *u32
- sq_array: *u32
- the index array, null with IORING_SETUP_NO_SQARRAY
- sqes: *u8
- sqe_bytes: u32
- 64, or 128 with IORING_SETUP_SQE128
- sqe_head: u32
- entries get_sqe handed out that submit has not published yet start here
- sqe_tail: u32
- and the next get_sqe hands out this one
- cq_entries: u32
- cq_mask: u32
- cq_head: *u32
- advanced by cqe_seen
- cq_tail: *u32
- advanced by the kernel
- cq_flags: *u32
- IORING_CQ_*
- cq_overflow: *u32
- cqes: *u8
- cqe_bytes: u32
- 16, or 32 with IORING_SETUP_CQE32
- sq_ring: *void
- sq_ring_bytes: u64
- cq_ring: *void
- the same mapping as sq_ring with IORING_FEAT_SINGLE_MMAP
- cq_ring_bytes: u64
- sqes_bytes: u64
